William c



(No Model.)

W. O. BAKER. SAFETY VENT FOR STEAM APPARATUS.

No. 473,722. Patented A r. 26, 1892.

l E c f MJAM Q Mo/L" 62MM WM V 3% UNITED STATES PATENT ulton.

VILLIAM C. BAKER, OF NEWV YORK, N. Y., ASSIGNOR TO THE BAKER HEATERCOMPANY, OF SAME PLACE.

SAFETY-VENT FOR STEAM APPARATUS.

SPECIFICATION forming part of Letters Patent No. 473,722, dated April26, 1892.

Application filed January 22, 1890. Serial No. 337,732. (No model) Toall whom it may concern.-

Be it known that I, WILLIAM C. BAKER, a citizen of the United States,residing at the city and State of New York, have invented an Improvementin Safety-Vents for Steam Apparatus, of which the following is aspecification.

In steam and hot-water apparatus, especially that made use of in heatingrailwaycars, there is danger from the apparatus being left withoutattention until the pressure accumulates to a dangerous height, andwhere safety-valves have been employed the valve is liable to becomeobstructed by oxidation and foreign substances,and if it opens bythepressure it often cannot be closed tightly again, and a sound that isdisagreeable to the passengers ensues. To rectify this difficulty, Iinvented a safety-vent, for which Letters Patent No. 372,289 weregranted to me, and in the same is described a flattened chamber havingone side or face thinner than the body and turned off true, so that withundue pressurethe thin side would blow off and give vent for the steam.I find that with proper care the safetyvent can be cast with a thin sideto the body in such a manner that the turning or truing is renderedunnecessary, and the breaking point or pressure will be sufficientlyuniform for general purposes.

In carrying out my invention I provide for relieving undue pressure andalso for extinguishing the fire in the car-heater, so that perfectsafety is obtained even when the car may be carelessly left without anattendant.

In the drawing I have represented my improvement by a diagrammaticvertical section.

The ordinary Baker heater contains a coil of pipe A within thefire-chamber B, and the hub 4 are sufficiently thick to be as strong asthe other parts of the steam or other apparatus; but the safety-face 5of the vent is much thinner, so that it will break away from theperiphery under the action of undue internal steam-pressure.

It is not necessary, as in my aforesaid patent, to make a hole in thehub 4 of larger diameter than the pipe H, to which the vent; is to bescrewed, because I find that the thin side of the safety-vent can becast so that it blows off at nearly the same internal pressure innumerous vents formed of the same size. To effect this object, the corearound which the vent is cast is made with care and supported at theopening for the pipe H, and the mold is formed so that the interiorsurface thereof is parallel to the face of the core; or, by preference,the safety-face is slightly thicker in the middle portion than at itsunion with the periphery, so that the separation under undue pressuretakes place all around the safety face at about the lines 9 9, thusfurnishing a large opening for the rapid escape of steam, and aconsequent reduction in the pressure. A screw-thread is to be cut in thehub 4 in order that the safety-vent may be screwed upon or removed fromthe vent-pipe II with facility, and the exterior of this hub 4 ispreferably polygonal, so that an ordinary wrench may be used in applyingor removing the vent.

This improved vent having the thin face, a casting without being turnedor trued is a new and useful article of manufacture that requires lessexpense in making than the vents heretofore constructed and is equallyefficacious.

The safety-vent I is represented as within the chamber L, the cover 10of which is removable to give access to the safety-vent, and from thischamber L a pipe N descends and opens into the fire-chamber, preferablyinto a portion of the ash-pit, so that the steam and any water that mayfoam over or issue through the vent when a rupture thereof takes placemay pass up into the fire and either extinguish such fire or soeffectually dampen the same as to remove further risk of injury to thecar. By removing the cover 10 access is given to the safety-Vent forremoving the same and placing another in position. It is not necessarythat the joint between the base and cover of the safetyvent beair-tight, as

the rush of steam and hot water will usually be sufficient to extinguishthe fire, and any leak at the joint will be immaterial, as the chamber Lis usually outside the car.

Any suitable safety-vent may be made use of in the chamber, from whichthe steam and Water are led to the fire to extinguish the same when thevent is ruptured or opened.

I claim as my inventionl. The combination, with the car-heatingapparatus having a fire-chamber, an expansion-vessel, and pipes in whichthe heated liquid is caused to circulate, of a safety-vent adapted to beruptured by undue pressure, an inclosure for the same, and a pipe fordirecting the steam or Water to the fire-chamber, substant'iallyasspecified.

2. The combination, with the car-heating apparatus having afire-chamber, an expansion-vessel, and circulating-pipes, of asafetyvent formed of cast metal with a thick body and a thin face,adapted to be blown off by undue pressure, a chamber inclosing suchsafety-vent, and a pipe from the same to the fire-chamber for directingthe steam and water upon the fire when the safety-vent is ruptured bythe pressure, substantially as set forth.

3. The combination, in a car-heating apparatus, of a fire-chamber, aclosed system of heating-pipes Within the car, and a Waterheating coilor vessel acted on by the fire, an expansion-vessel, a safety-ventadapted to be ruptured by undue pressure, a pipe connecting the samewith the system of heating-pipes,

a closed chamber into which the steam passes when the safety-vent isruptured, and a pipe leading from such chamber to the fire,substantially as set forth.

Signed by me this 13th day of January, 1890.

W. o. BAKER.

Vitnesses:

A. E. SMITH, F. B. WEAVER.

